Fixed typos, finished comment on test and added new assert.

lib/Doctrine/DBAL/Schema/Comparator.php

@@ -46,7 +46,7 @@ class Comparator
     /**
      * Returns a SchemaDiff object containing the differences between the schemas $fromSchema and $toSchema.
      *
-     * The returned diferences are returned in such a way that they contain the
+     * The returned differences are returned in such a way that they contain the
      * operations to change the schema stored in $fromSchema to the schema that is
      * stored in $toSchema.
      *
@@ -272,7 +272,7 @@ class Comparator
 
     /**
      * Try to find columns that only changed their name, rename operations maybe cheaper than add/drop
-     * however ambiguouties between different possibilites should not lead to renaming at all.
+     * however ambiguities between different possibilities should not lead to renaming at all.
      *
      * @param TableDiff $tableDifferences
      */

tests/Doctrine/Tests/DBAL/Schema/ComparatorTest.php

@@ -783,7 +783,10 @@ class ComparatorTest extends \PHPUnit_Framework_TestCase
 
 
     /**
-     * You can get multiple drops for a FK when 
+     * You can get multiple drops for a FK when a table referenced by a foreign
+     * key is deleted, as this FK is referenced twice, once on the orphanedForeignKeys
+     * array because of the dropped table, and once on changedTables array. We
+     * now check that the key is present once.
      */
     public function testAvoidMultipleDropForeignKey()
     {
@@ -804,6 +807,7 @@ class ComparatorTest extends \PHPUnit_Framework_TestCase
         $diff = $c->compare($oldSchema, $newSchema);
 
         $this->assertCount(0, $diff->changedTables['foo']->removedForeignKeys);
+        $this->assertCount(1, $diff->orphanedForeignKeys);
     }